Overview

Comprehensive Description

Description

Typical body shape of a pipid frog; tentacle below eye 0.5 of the eye diameter; foot with three horny claws.

A medium-sized clawed frog with button-like protruding eyes situated dorsally. Body flattened. Adults measure 38–60mm (SVL). The subocular tentacles are well developed, reaching about 0.6–1 of the eye diameter. The skin is almost smooth. Starting at the posterior border of the eye, a double line of elongate unpigmented flat sensory tubercles (lateral line sense organs) is arranged in roughly alternating order. The outer line comprises 20–29 tubercles set at right angles to the body axis. The inner one runs parallel to the latter, comprising about 16–20 tubercles. Furthermore, 3–7 pairs of these tubercles appear in the neck region, and 10–14 ones are found on the border of the lower jaw, set at right angles to the mouth. Like all of the dorsal surface, this part of the skin is scattered with numerous minute asperities which are equally unpigmented. Some of these may also be found on the fingers which are covered with numerous minute grooves. On breeding males, the outer part of the fingers is black. The dermal lobes above the vent are better developed in females. The web of the hind limbs is fully developed. Toes 3–5 have black horny claws. Metatarsal tubercle without claw. 2n = 36.

Coloration: Dorsal parts of body and limbs drab olive with large black patches that are sometimes vaguely defined. The iris shows a silver-grey glimmer. The venter is whitish to orange yellow. Some darker patches occasionally appear on the throat and on the thighs. A single female had the belly scattered with black spots. Distinctive ventral designs were reported from Ghanian frogs (Poynton 1964c). According to Loumont (1984), the dorsal patches of animals from Tanzania, Malawi and Zimbabwe are often arranged in two longitudinal rows. Mertens (1955b) mentions a female from Tanzania whose venter showed smoky-gray patches and a young specimen whose venter was plain white. In alcohol the dorsum turns almost completely gray olive, and the original black patches are hardly visible. The venter turns gray white, and black spots remain visible.

Voice: So far, it has not yet been registered at Comoé National Park. According to Schiøtz (1963), the call sounds like a rather low "pink-pink" resembling the sound produced by a spoon knocking against a pan. According to Vigny (1979), animals from Malawi produce a sequence of rattling "trra-trra" calls lasting 0.15–0.21 sec, the dominant frequency being 1.1 kHz. She describes two types of calls. Picker (1983) has also published sonagrams. These calls lasts 0.15 to 0.20 sec, comprising 5–6 pulses (dominant frequency: 0.8–0.9 kHz). Wager (1986) describes the call as "turrr", comparing it to the sound produced by a pencil vibrating against a glass pane. According to Lambiris (1988), two soft calls per second are uttered under water. Passmore & Carruthers (1995) report short "metallic" calls produced under water at intervals of 0.15 seconds. The vocal apparatus of the male has been examined by Loumont (1981).

This account was taken from Rödel, M.-O. (2000), Herpetofauna of West Africa vol. I. Amphibians of the West African Savanna, with kind permission from Edition Chimaira publishers, Frankfurt am Main.For references in the text, see here

Loveridge, A. (1929). ''East African reptiles and amphibians in the United States National Museum.'' Smithsonian Institution, U.S. National Museum Bulletin, 151, 1-135.

Loveridge, A. (1930). ''A list of the Amphibia of the British territories in East Africa (Uganda, Kenya Colony, Tanganyika Territory, and Zanzibar), together with keys for the diagnosis of the species.'' Proceedings of the Zoological Society of London, 1930, 7-32.

Loveridge, A. (1932). ''New frogs of the genera Arthroleptis and Hyperolius from Tanganyika Territory.'' Proceedings of the Biological Society of Washington, 45, 61-64.

Loveridge, A. (1935). ''Scientific results of an expedition to rain forest regions in Eastern Africa, I. New reptiles and amphibians from East Africa.'' Bulletin of the Museum of Comparative Zoology, Harvard, 79, 1-19.

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Description

Typical body shape of a pipid frog; tentacle below eye 0.5 of the eye diameter; foot with three horny claws.

A medium-sized clawed frog with button-like protruding eyes situated dorsally. Body flattened. Adults measure 38-60mm (SVL). The subocular tentacles are well developed, reaching about 0.6-1 of the eye diameter. The skin is almost smooth. Starting at the posterior border of the eye, a double line of elongate unpigmented flat sensory tubercles (lateral line sense organs) is arranged in roughly alternating order. The outer line comprises 20-29 tubercles set at right angles to the body axis. The inner one runs parallel to the latter, comprising about 16-20 tubercles. Furthermore, 3-7 pairs of these tubercles appear in the neck region, and 10-14 ones are found on the border of the lower jaw, set at right angles to the mouth. Like all of the dorsal surface, this part of the skin is scattered with numerous minute asperities which are equally unpigmented. Some of these may also be found on the fingers which are covered with numerous minute grooves. On breeding males, the outer part of the fingers is black. The dermal lobes above the vent are better developed in females. The web of the hind limbs is fully developed. Toes 3-5 have black horny claws. Metatarsal tubercle without claw. 2n = 36.

Coloration: Dorsal parts of body and limbs drab olive with large black patches that are sometimes vaguely defined. The iris shows a silver-grey glimmer. The venter is whitish to orange yellow. Some darker patches occasionally appear on the throat and on the thighs. A single female had the belly scattered with black spots. Distinctive ventral designs were reported from Ghanian frogs (Poynton 1964c). According to Loumont (1984), the dorsal patches of animals from Tanzania, Malawi and Zimbabwe are often arranged in two longitudinal rows. Mertens (1955b) mentions a female from Tanzania whose venter showed smoky-gray patches and a young specimen whose venter was plain white. In alcohol the dorsum turns almost completely gray olive, and the original black patches are hardly visible. The venter turns gray white, and black spots remain visible.

Voice: So far, it has not yet been registered at Comoé National Park. According to Schiøtz (1963), the call sounds like a rather low "pink-pink" resembling the sound produced by a spoon knocking against a pan. According to Vigny (1979), animals from Malawi produce a sequence of rattling "trra-trra" calls lasting 0.15-0.21 sec, the dominant frequency being 1.1 kHz. She describes two types of calls. Picker (1983) has also published sonagrams. These calls lasts 0.15 to 0.20 sec, comprising 5-6 pulses (dominant frequency: 0.8-0.9 kHz). Wager (1986) describes the call as "turrr", comparing it to the sound produced by a pencil vibrating against a glass pane. According to Lambiris (1988), two soft calls per second are uttered under water. Passmore & Carruthers (1995) report short "metallic" calls produced under water at intervals of 0.15 seconds. The vocal apparatus of the male has been examined by Loumont (1981).

This account was taken from Rödel, M.-O. (2000), Herpetofauna of West Africa vol. I. Amphibians of the West African Savanna, with kind permission from Edition Chimaira publishers, Frankfurt am Main.For references in the text, see here

Loveridge, A. (1929). ''East African reptiles and amphibians in the United States National Museum.'' Smithsonian Institution, U.S. National Museum Bulletin, 151, 1-135.

Loveridge, A. (1930). ''A list of the Amphibia of the British territories in East Africa (Uganda, Kenya Colony, Tanganyika Territory, and Zanzibar), together with keys for the diagnosis of the species.'' Proceedings of the Zoological Society of London, 1930, 7-32.

Loveridge, A. (1932). ''New frogs of the genera Arthroleptis and Hyperolius from Tanganyika Territory.'' Proceedings of the Biological Society of Washington, 45, 61-64.

Loveridge, A. (1935). ''Scientific results of an expedition to rain forest regions in Eastern Africa, I. New reptiles and amphibians from East Africa.'' Bulletin of the Museum of Comparative Zoology, Harvard, 79, 1-19.

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Distribution

Range Description

This species appears to occur in three separate populations: from eastern Cte dIvoire and Burkina Faso eastward across Sudan-Guinea zone to northeastern Democratic Republic of Congo, South Sudanwestwards to Dahomey,the Mozambique plain and its fringes northwards from Lake St Lucia in Zululand, Malawi and Zambia lowlands, Okavango area, Tanganyika, Zanzibar and Kenya;from the Kenyan coast, south to northeastern South Africa, Swaziland, northern Botswana, northeastern Namibia, and southeastern Angola;and from the Ennedi in northeastern Chad (Poynton 1964). It seems likely that many records from the inland parts of Tanzania currently assigned to this species should in fact be referred to Xenopus borealis, and the distribution maps probably records this species as occurring much too widely in this country. It is mainly a lowland species, but probably occurs up to at least 2,000 m asl.

Loveridge, A. (1929). ''East African reptiles and amphibians in the United States National Museum.'' Smithsonian Institution, U.S. National Museum Bulletin, 151, 1-135.

Loveridge, A. (1930). ''A list of the Amphibia of the British territories in East Africa (Uganda, Kenya Colony, Tanganyika Territory, and Zanzibar), together with keys for the diagnosis of the species.'' Proceedings of the Zoological Society of London, 1930, 7-32.

Loveridge, A. (1932). ''New frogs of the genera Arthroleptis and Hyperolius from Tanganyika Territory.'' Proceedings of the Biological Society of Washington, 45, 61-64.

Loveridge, A. (1935). ''Scientific results of an expedition to rain forest regions in Eastern Africa, I. New reptiles and amphibians from East Africa.'' Bulletin of the Museum of Comparative Zoology, Harvard, 79, 1-19.

Loveridge, A. (1929). ''East African reptiles and amphibians in the United States National Museum.'' Smithsonian Institution, U.S. National Museum Bulletin, 151, 1-135.

Loveridge, A. (1930). ''A list of the Amphibia of the British territories in East Africa (Uganda, Kenya Colony, Tanganyika Territory, and Zanzibar), together with keys for the diagnosis of the species.'' Proceedings of the Zoological Society of London, 1930, 7-32.

Loveridge, A. (1932). ''New frogs of the genera Arthroleptis and Hyperolius from Tanganyika Territory.'' Proceedings of the Biological Society of Washington, 45, 61-64.

Loveridge, A. (1935). ''Scientific results of an expedition to rain forest regions in Eastern Africa, I. New reptiles and amphibians from East Africa.'' Bulletin of the Museum of Comparative Zoology, Harvard, 79, 1-19.

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Diagnostic Description

This is a large aquatic frog. The dorsum is gray with scattered darker blotches, and the ventral surface is light with bright yellow below the legs. Some faint gray shading is often present in the pectoral region. The eyes are small with round pupils and a conspicuous sub-ocular tentacle that is greater than ½ the diameter of the eye. Lateral line organs are clearly visible, appearing as a series of 22 – 27 ‘stitches’ along each side. The toes are fully webbed and the tips of the inner three toes end in darkly pigmented claws (Text from Harper et al., 2010).

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Ecology

Habitat

Habitat and Ecology

It is a water-dependent species, using both temporary and permanent ponds, and also streams and rivers in the dry season. In West Africa it occurs mainly in the dry savannah and northern humid savannah zones, preferring drier condition to Xenopus laevis. It is found in agricultural and other altered habitats. It seldom occurs in forests. It also prefers hotter conditions compared with X. laevis, and uses muddier waters. It breeds in still water pools.

This aquatic species is found in lowland savanna, including permanent and temporary ponds, streams and rivers. It occurs primarily in lowland areas, but it may occur up to 2000 m. It tolerates habitat modification and can be found in agricultural areas (Harper et al., 2010).

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Breeding takes place in muddy pools. The breeding behavior of this species is not well known. It is likely similar to that of other species in the genus in which eggs are attached to submerged rocks or vegetation. The eggs are small and darkly pigmented. Tadpoles are large with long tentacles that are at least ¼ the total length. Tadpoles lack keratinized mouthparts and form schools, feeding on unicellular algae in the water column. All Xenopus spp. lack tongues, and feed by sucking in aquatic prey, sometimes with the aid of their long fingers (Text from Harper et al., 2010).

CCTATATCTAATTTTTGGTGCTTGAGCAGGCATGGTGGGTACAGCATTAAGTCTATTAATTCGAGCTGAATTAAGTCAACCCGGAACTTTACTAGGAGACGATCAGATTTATAACGTTATCGTTACAGCACATGCCTTTATTATAATTTTCTTCATAGTAATACCCATCATAATTGGTGGTTTTGGAAACTGACTAGTTCCATTAATGATCGGAGCACCTGACATGGCCTTTCCTCGAATAAATAATATAAGCTTCTGACTCTTACCTCCATCATTTCTTCTTTTATTAGCCTCATCTGGGGTCGAAGCAGGTGCAGGAACTGGTTGAACCGTCTATCCACCCTTGGCTGGAAACTTAGCACATGCTGGGGCATCAGTAGATTTAACTATTTTCTCTCTCCATTTAGCCGGTGTATCTTCCATTTTGGGTGCAATTAACTTCATTACCACCACTATTAACATAAAACCACCCGCTATATCCCAGTATCAAACACCCTTATTCGTCTGGTCTGTGTTAATTACCGCCGTTCTGCTGCTCTTATCTCTACCAGTCTTAGCTGCAGGTATCACAATACTTTTAACTGATCGAAATCTAAACACCACCTTTTTCGACCCTGCCGGAGG-- end --

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Life History, Abundance, Activity, and Special Behaviors

Spawn: Eggs have not yet been found at Comoé National Park. According to Arnoult & Lamotte (1968), eggs were attached singly to aquatic plants. Swisher (1969) reports that eggs were deposited on rocks and on leaves. Data concerning egg and clutch size are not published. In Xenopus laevis the egg diameter is 3 mm (Rose 1950).Tadpoles: A typical pipid larva whose broad mouth resembles that of a catfish, lacking both horny beaks and teeth. Long, thin tentacles are situated on both sides of the mouth, reaching beyond the dorsal base of the tail fins when held against the body. The dorsal fin is considerably less broader than the ventral one. The ventral emargination of the fin between body and vent is rather marked. The tip of the tail is curved upward more visibly than in Silurana tropicalis. The coloration of larvae inhabiting muddy pools is transparent or cream. In rather somber habitats, the entire tail fin shows a blackish hue. Total length is 2.6–3 times the body length. The tail height is 2–2.3 times the body length. The intestines often shows a silvery glimmer. A paired spiracle is present on the venter.In 1993, two weeks after the rainy season had set in, we found a larva measuring 60mm (TL) whose limbs had not yet emerged. Two weeks later, the tadpole metamorphosed, having reached a length of 21.8 mm. Some example measures and weights (TL in mm, weight in g): 42/ 0.24; 45/ 0.48; 48/ 0.75; 55/ 0.68; 58/ 1.44; 63/ 1.53; 68/ 1.38; 72/ 1.75. Metamorphosis set in when the tadpoles had reached a TL of more than 5 cm. The largest tadpole ever collected in Comoé National Park measured 100mm, showing fully developed hind limbs. Freshly metamorphosed young measured more than 20 mm. The largest tadpole collected by Noble (1924) measured 87mm. Stewart (1967) writes that the length of the tentacles corresponds to more than ¼ of the TL. According to Lambiris (1988), tadpoles reach a TL of 70 mm, whereas Arnoult & Lamotte (1968) mention animals measuring 98 mm (TL). According to the latter, the tentacles begin to emerge at a TL of 7 mm (BL: 2.5 mm). At this stage, exterior gills have already been reduced almost completely. Freshly metamorphosed animals are reported to measure 40 mm (SVL, Arnoult & Lamotte 1968).X. muelleri spends the dry season in the bank zone of the rivers, migrating into the savanna as soon as heavy rainfall sets in. I have found them in the gallery forest only during those migrations. As X. muelleri reappears almost immediately even in ponds far away from the permanent rivers, it seems highly probable that some frogs survive the dry season in the mud of those ponds. In Nigeria, Schiøtz (1963) found animals under humid layers of leaf litter in the dry season. According to Noble (1924) they buried themselves in the mud when ponds dried out. If it happens to rain at night, the frogs often move between different ponds. Drift fences with pitfall traps arranged at one pool have shown that even well-filled ponds are often left and/or re-colonized by these animals. Short migrations made by adult specimens are referred to in Walker (1968), too. According to this author, the species call both during day and night.Reproduction apparently takes place exclusively in a rather restricted number of ponds, so I seldom succeeded in recording tadpoles of X. muelleri (Rödel 1998b). They seem to be comparatively common in large ponds, but occur occasionally in puddles containing less than 200 l or in residuary ponds, e.g. those found in the dry beds of seasonal brooks. As the tadpoles inhabiting large ponds always form larger swarms whereas those found in puddles are less numerous or even solitary, it is highly probable that the latter have been washed accidentally into these habitats during periods of heavy rainfall. Like the tadpoles of S. tropicalis, those of X. muelleri filter their food in mid-water, swimming either on the spot, or moving forward rather slowly. In flight, however, these animals can reach astonishingly high speeds, jumping occasionally even above the surface. According to Stewart (1967) and Lambiris (1988), the tadpole of this species usually swim horizontally. In Comoé National Park I observed them always with the head directed downward. Stewart (1967) confirms that swarms of 20–30 specimens are found mostly in mid-water.The observations made by Joger (1982) apparently speak in favor of a rather extended breeding season: he found various stages of development in one and the same pond. At Comoé National Park, tadpoles occur throughout the rainy season. The breeding ponds in Ghana are said to dry up before September (Arnoult & Lamotte 1968). In Nigeria, Walker (1968) found numerous mummified tadpoles, mainly during the months of November-December. Noble (1924) identified green algae and diatoms as food items in the alimentary tracts of tadpoles. Adults’ stomachs contained arthropods and small Xenopus tadpoles. Haagner & Haagner (1997) report on storks preying on X. muelleri in Natal.

Loveridge, A. (1929). ''East African reptiles and amphibians in the United States National Museum.'' Smithsonian Institution, U.S. National Museum Bulletin, 151, 1-135.

Loveridge, A. (1930). ''A list of the Amphibia of the British territories in East Africa (Uganda, Kenya Colony, Tanganyika Territory, and Zanzibar), together with keys for the diagnosis of the species.'' Proceedings of the Zoological Society of London, 1930, 7-32.

Loveridge, A. (1932). ''New frogs of the genera Arthroleptis and Hyperolius from Tanganyika Territory.'' Proceedings of the Biological Society of Washington, 45, 61-64.

Loveridge, A. (1935). ''Scientific results of an expedition to rain forest regions in Eastern Africa, I. New reptiles and amphibians from East Africa.'' Bulletin of the Museum of Comparative Zoology, Harvard, 79, 1-19.

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Life History, Abundance, Activity, and Special Behaviors

Spawn: Eggs have not yet been found at Comoé National Park. According to Arnoult & Lamotte (1968), eggs were attached singly to aquatic plants. Swisher (1969) reports that eggs were deposited on rocks and on leaves. Data concerning egg and clutch size are not published. In Xenopus laevis the egg diameter is 3 mm (Rose 1950).Tadpoles: A typical pipid larva whose broad mouth resembles that of a catfish, lacking both horny beaks and teeth. Long, thin tentacles are situated on both sides of the mouth, reaching beyond the dorsal base of the tail fins when held against the body. The dorsal fin is considerably less broader than the ventral one. The ventral emargination of the fin between body and vent is rather marked. The tip of the tail is curved upward more visibly than in Silurana tropicalis. The coloration of larvae inhabiting muddy pools is transparent or cream. In rather somber habitats, the entire tail fin shows a blackish hue. Total length is 2.6-3 times the body length. The tail height is 2-2.3 times the body length. The intestines often shows a silvery glimmer. A paired spiracle is present on the venter.In 1993, two weeks after the rainy season had set in, we found a larva measuring 60mm (TL) whose limbs had not yet emerged. Two weeks later, the tadpole metamorphosed, having reached a length of 21.8 mm. Some example measures and weights (TL in mm, weight in g): 42/ 0.24; 45/ 0.48; 48/ 0.75; 55/ 0.68; 58/ 1.44; 63/ 1.53; 68/ 1.38; 72/ 1.75. Metamorphosis set in when the tadpoles had reached a TL of more than 5 cm. The largest tadpole ever collected in Comoé National Park measured 100mm, showing fully developed hind limbs. Freshly metamorphosed young measured more than 20 mm. The largest tadpole collected by Noble (1924) measured 87mm. Stewart (1967) writes that the length of the tentacles corresponds to more than ¼ of the TL. According to Lambiris (1988), tadpoles reach a TL of 70 mm, whereas Arnoult & Lamotte (1968) mention animals measuring 98 mm (TL). According to the latter, the tentacles begin to emerge at a TL of 7 mm (BL: 2.5 mm). At this stage, exterior gills have already been reduced almost completely. Freshly metamorphosed animals are reported to measure 40 mm (SVL, Arnoult & Lamotte 1968).X. muelleri spends the dry season in the bank zone of the rivers, migrating into the savanna as soon as heavy rainfall sets in. I have found them in the gallery forest only during those migrations. As X. muelleri reappears almost immediately even in ponds far away from the permanent rivers, it seems highly probable that some frogs survive the dry season in the mud of those ponds. In Nigeria, Schiøtz (1963) found animals under humid layers of leaf litter in the dry season. According to Noble (1924) they buried themselves in the mud when ponds dried out. If it happens to rain at night, the frogs often move between different ponds. Drift fences with pitfall traps arranged at one pool have shown that even well-filled ponds are often left and/or re-colonized by these animals. Short migrations made by adult specimens are referred to in Walker (1968), too. According to this author, the species call both during day and night.Reproduction apparently takes place exclusively in a rather restricted number of ponds, so I seldom succeeded in recording tadpoles of X. muelleri (Rödel 1998b). They seem to be comparatively common in large ponds, but occur occasionally in puddles containing less than 200 l or in residuary ponds, e.g. those found in the dry beds of seasonal brooks. As the tadpoles inhabiting large ponds always form larger swarms whereas those found in puddles are less numerous or even solitary, it is highly probable that the latter have been washed accidentally into these habitats during periods of heavy rainfall. Like the tadpoles of S. tropicalis, those of X. muelleri filter their food in mid-water, swimming either on the spot, or moving forward rather slowly. In flight, however, these animals can reach astonishingly high speeds, jumping occasionally even above the surface. According to Stewart (1967) and Lambiris (1988), the tadpole of this species usually swim horizontally. In Comoé National Park I observed them always with the head directed downward. Stewart (1967) confirms that swarms of 20-30 specimens are found mostly in mid-water.The observations made by Joger (1982) apparently speak in favor of a rather extended breeding season: he found various stages of development in one and the same pond. At Comoé National Park, tadpoles occur throughout the rainy season. The breeding ponds in Ghana are said to dry up before September (Arnoult & Lamotte 1968). In Nigeria, Walker (1968) found numerous mummified tadpoles, mainly during the months of November-December. Noble (1924) identified green algae and diatoms as food items in the alimentary tracts of tadpoles. Adults stomachs contained arthropods and small Xenopus tadpoles. Haagner & Haagner (1997) report on storks preying on X. muelleri in Natal.

Loveridge, A. (1929). ''East African reptiles and amphibians in the United States National Museum.'' Smithsonian Institution, U.S. National Museum Bulletin, 151, 1-135.

Loveridge, A. (1930). ''A list of the Amphibia of the British territories in East Africa (Uganda, Kenya Colony, Tanganyika Territory, and Zanzibar), together with keys for the diagnosis of the species.'' Proceedings of the Zoological Society of London, 1930, 7-32.

Loveridge, A. (1932). ''New frogs of the genera Arthroleptis and Hyperolius from Tanganyika Territory.'' Proceedings of the Biological Society of Washington, 45, 61-64.

Loveridge, A. (1935). ''Scientific results of an expedition to rain forest regions in Eastern Africa, I. New reptiles and amphibians from East Africa.'' Bulletin of the Museum of Comparative Zoology, Harvard, 79, 1-19.

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Relevance to Humans and Ecosystems

Benefits

Uses

X. muelleri is the second most traded frog species in Nigeria. In Burkina Faso, however, they seem to be avoided, so while they appear in the area, they are not a major source of animal protein. Frogs are an integral part of the economy in areas with large frog populations. Villagers are employed to catch and prepare frogs because they are an "important international trading item." Aside from their value as an essential food source, frogs and, more commonly, toads may also be used for cultural reasons and as traditional medicine in areas where Western medicine is not available. Though they are among the most traded frog species in Nigeria, only a few people interviewed "perceived a decline" (Mohneke, 2010).